title: Identification of proteins associated with polyhydroxybutyrate granules from Herbaspirillum seropedicae SmR1--old partners, new players.
abstract: Herbaspirillum seropedicae is a diazotrophic ß-Proteobacterium found associated with important agricultural crops. This bacterium produces polyhydroxybutyrate (PHB), an aliphatic polyester, as a carbon storage and/or source of reducing equivalents. The PHB polymer is stored as intracellular insoluble granules coated mainly with proteins, some of which are directly involved in PHB synthesis, degradation and granule biogenesis. In this work, we have extracted the PHB granules from H. seropedicae and identified their associated-proteins by mass spectrometry. This analysis allowed us to identify the main phasin (PhaP1) coating the PHB granule as well as the PHB synthase (PhbC1) responsible for its synthesis. A phbC1 mutant is impaired in PHB synthesis, confirming its role in H. seropedicae. On the other hand, a phaP1 mutant produces PHB granules but coated mainly with the secondary phasin (PhaP2). Furthermore, some novel proteins not previously described to be involved with PHB metabolism were also identified, bringing new possibilities to PHB function in H. seropedicae.
authors.affiliation: Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, Brazil.
authors.forename: Evandro F
authors.initials: EF
authors.lastname: Tirapelle
authors.forename: Marcelo
authors.initials: M
authors.lastname: Müller-Santos
authors.forename: Michelle Z
authors.initials: MZ
authors.lastname: Tadra-Sfeir
authors.forename: Marco A S
authors.initials: MA
authors.lastname: Kadowaki
authors.forename: Maria B R
authors.initials: MB
authors.lastname: Steffens
authors.forename: Rose A
authors.initials: RA
authors.lastname: Monteiro
authors.forename: Emanuel M
authors.initials: EM
authors.lastname: Souza
authors.forename: Fabio O
authors.initials: FO
authors.lastname: Pedrosa
authors.forename: Leda S
authors.initials: LS
authors.lastname: Chubatsu
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D042803:Herbaspirillum / Q000235:genetics / Q000378:metabolism*; D006885:Hydroxybutyrates / Q000378:metabolism*; D013058:Mass Spectrometry
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D006885:Hydroxybutyrates; C118828:PHAP protein, Bacteria